This invention relates to animated decorations for the home, to toys, and to advertising displays, and more particularly to an improved system for moving objects of interest around a circuitous path, suspended on lines that are virtually invisible.
In the fields of advertising, toys, and seasonal decorations, the appeal of dynamic displays is widely recognized. That appeal is enhanced if the objects appear to fly through the air with no visible means of support, especially if popular mythology attributes magical flight to those objects, as it does, for example, to Santa and his reindeer.
Several patents have been issued for dynamic displays that involve similar basic elements: an endless loop revolving on a series of horizontal pulleys or sprockets, one of which is driven by a motor, and objects of interest suspended from that loop. Such systems have an inherent problem: the weight of each suspended object pulls down on the loop at its point of attachment, so it tends to pull the loop off a pulley or sprocket at that point. Therefore, previous inventions have required substantial material for the loop, such as chain, cable, or belt. Some examples are: U.S. Pat. No. 3,849,919 (Gravelle et al) and U.S. Pat. No. 3,735,513 (Constant, Jr. et al), which involve cable; U.S. Pat. No. 89,390 (McOsker), which involves chain; and U.S. Pat. No. 3,858,339 (Short) and U.S. Pat. No. 1,993,545 (Gentry et al), which involve different forms of endless belt. The present invention better solves the problem with pulleys that compensate dynamically for changes in the loop, and it uses a loop of ordinary line, such as fishline, which is much less expensive, virtually invisible, and allows much longer circuits of movement. The pulley system can be installed easily with a series of tacks on the top or side edges of door frames or window frames, so no unsightly holes are left after the system is put away, which is an advantage especially in home decorations and toys.
Endless loop transport systems are also used for moving heavy objects and people, as in ski lifts or mountain cable cars, but these systems involve a somewhat different principle: in all critical areas the endless loop rides on top of vertically mounted pulleys, and each of the objects is suspended by means of a rigid member that has a hook at its top end where it attaches to the loop. The attachment rides over the supporting pulley, so the object does not tend to pull the loop off the pulley. Horizontal pulleys are used only for reversing direction at either end of a run, and there arrangements must be made for otherwise supporting the weight of the object and for safety. Such systems are limited to transport along essentially straight courses.